Method for closing bores at workpieces and improved plug constructions for the performance of the aforesaid method

ABSTRACT

A plug for closing the bores of workpieces as well as a method for closing such bores wherein there is provided a plug sleeve which is inserted into the bore of the workpiece. An expanding member is driven into the bore of the plug sleeve for progressively radially expanding the plug in the axial direction thereof. This causes anchoring means at the outside surface of the sleeve to fixedly engage with the material of the wall of the bore of the workpiece. The expanding member should possess a substantially ball-like configuration at least at the region intended to bear against the bore of the plug sleeve. This expanding member may be preferably in the form of a ball.

nited States, Patent 7 [191 v irmann 451v July 23, 1974 [54] METHOD FORCLOSING BORES AT 2,821,323 l/l958 Lee 220/24.5 WORKPIECES AND IMPROVEDPLUG 2,855,003 10/1958 Thaxton.... 220/245 3,451,583 6/1969 Lee l220/245 CONSTRUCTIONS FOR THE 3,525,453 8/1970 Lee 220/245 PERFORMANCEOF THE AFORESAID METHOD Inventor: Georg Hirmann, Zurich,

Switzerland Assignee: Dr. lng. Koenlg AG, Dietikon,

Switzerland Filed: July 6, 1971 Appl. No.: 159,647

U.S. Cl. 220/245, 29/522 Int. Cl 865d 39/12 Field of Search 29/522, 523,521, 507;

References Cited UNITED STATES PATENTS 11/1951 Zimmerman 220/245 PrimaryExaminer-George E. Lowrance Attorney, Agent, or FirmWerner W. Kleeman[57] ABSTRACT A plug for closing the bores of workpieces as well as amethod for closing such bores wherein there is provided a plug sleevewhich is inserted into the bore of 12 Claims, 6 Drawing FiguresPATENTEUJULNW 4 3.825.146

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SHEET 3 0F '3 '1 METHOD FOR CLOSING BORIES AT WORKPIECES AND IMPROVEDPLUG CONSTRUCTIONS FOR THE PERFORMANCE OF THE AFORESAID METHODBACKGROUND or THE INVENTION The present invention relates to a new andimproved method for closing bores in or at workpieces with the aid of aradially expandable plug which can be inserted in such bore.Additionally, this invention is concerned with improved plugconstructions for the performance of the aforesaid method.

It is already known to the art to insert a hollow plug which is closedat its bottom into a stepped bore of a metallic workpiece for thepurpose of sealing or closing such bore. This plug is provided with aninside taper or cone. Thereafter, through the application of force upona conical pin this pin is driven internally into the plug. Due to suchaction the walls of the plug are spread apart, and owing to suchexpansion this plug is fixedly seated in the bore. A drawback of thisstate-of-the-art construction of plug and its mode of insertion into thebore to be closed is that it is necessary to exert a relatively largedriving force upon the pin, since with the same conicalness of theinside taper and the pin the entire length of the plug wall mustsimultaneously come to bear against the bore and the entire length ofthe outside surface or jacket of the plug must be simultaneouslyexpanded. Additionally, the friction between the inside taper of theplug and the pin is very large during such time as the pin is driveninto the plug, so that the practically attainable holding force of theplug in the'bore and its sealing action are limited.

SUMMARY OF THEINVENTION Therefore, a primary objective of the presentinvention is to reduce the force which is required for expanding theplug and to improve upon its retention within the bore. I

Still a further significant object of the present invention is directedto a novel method of sealing a bore at a workpiece which improves uponthe prior art techniques discussed above, and further relates toimproved constructions of plugs for carrying out the inventive method.

Another significant object of the present invention relatesto a novelplug design for use in the sealing of bores wherein the plug isconstructed such that it is progressively radially expanded in axialdirection after it has been placed within the bore which is to besealed.

Now, in keeping with the aforementioned objectives of this invention themethod aspects thereof contemplate progressively radially expanding thesleeve member of the plug in axial direction after insertion of the itsbroader sense to mean a crownedor spherical like the bores whileexpending a comparatively slight amount of force. Plugs of this type areespecially suitable for sealing or closing bores in conduit systemsthrough which there is conveyed liquid or gas under pressure. Therefore,the utilization of the method aspects of this development as well as theplugs constructed in accordance with this invention in the field ofhydraulic and pneumatic power'transmissionand control systems as well asin coolingand lubricating systems has found to be particularlyadvantageous. Those skilled in this particular art will recognize thatthe invention has vast applicability in a number of differentenvironments, particularly when it is desired to close or seal a'borewithin any type of workpiece, whether such be a conduit, duct, channel,chamber or otherwise.

BRIEF DESCRIPTION-OF THE DRAWINGS The invention will be betterunderstood and objects other than those set forth above will becomeapparent when consideration is given to the following detaileddescription thereof. Such description makes reference to the annexeddrawings, wherein:

FIG. 1 is a longitudinal sectional view through a plug together with itsplug expanding element here shown in the form of a sphere or ball and ina condition prior to insertion of this plug construction into the boreof a workpiece;

FIG. 2 is a fragmentary longitudinal sectional view through a plug ofthe type shown in FIG. 1 but this time inserted in the bore of theworkpiece and wherein the expanding ball or sphere has been driven intothe interior of the plug;

FIG. 3 is a longitudinal sectional view analogous to the showing of FIG.2 but through a modified version of plug employing a funnel-shapedbottom or floor;

FIG. 4 is a longitudinal sectional view, again analogous to the showingof FIG. 2, through a further embodiment of plug equipped with anoutwardly projecting collar;

FIG. 5 is a longitudinal sectional view through an embodiment of plughaving a turned-in or rolled-in flange or edge; and

FIG. 6 is an enlarged schematic illustration of the rolling or squeezingmovement during penetration of the teeth of the plug into the materialbounding the bore of the workpiece.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Deseribingnow thedrawings, the exemplary embodiment of plug construction serving for theclosing of bores as illustrated in FIG. 1 will be seen to encompass anexpandable sleeve or jacket 1 and an expanding member, here shown in theform of a ball or sphere 2, which is inserted in the expandablesleeve 1. The ball 2 is fixedly retained at the region of the sleeveopening 17 by providing a slightly inwardly turned or flanged marginaledge 3, as shown. A number of substantially ring-shaped, sharp-edgedteeth or ribs 8 defining an-. choring ridges are provided at the outerperiphery of the sleeve lat the central region thereof, these teeth 8possessing a preferably sawtooth-like configuration and being arrangedin tandem or behind one another. Teeth 8 are preferably fabricated atthe sleeve 1 by a rolling or tapping operation. The inside diameter ofthe cylindrical bore 6 of the sleeve 1 is somewhat smaller than thediameter of the ball or sphere 2. Furthermore, the floor or bottom 9 ofthe plug sleeve 1 possesses a larger wall thickness than the side walls18 of such sleeve.

Now, the plug construction of FIG. 1 which has me viously mountedtherein a ball or a sphere 2 serving as the plug expanding element isdestined to be inserted into the bore 10 of any suitable workpiece 4.Accordingly, this bore 10 of the workpiece 4 is bored out, correspondingto the length of the plug itself and so as to possess a diameter whichcorresponds to the outside diameter of the plug sleeve 1. Through theprovision of this bore 10 at the workpiece 4 there is formed a shoulder5 against which bears the plug when it is inserted therein. Now, inorder to ensure thatthe plug itself will remain non-displaceably andsealingly seated within the workpiece bore and also will be capable ofwithstanding considerable pressure within such bore, for

instance for valves of hydraulic installations, the sleeve I l isexpanded with the aid of the expanding ball 2. This can be accomplishedby driving the ball 2 into the interior of the sleeve 1, for instancewith the aid of a suitable mandrel or punch, and until this ball 2 hasapproximately assumed the position illustrated in FIG. 2. The length ofthe path through which the ball 2 should be displaced should at leastcorrespond to one-half of the diameter of such a ball. Owing to thedriving of the ball 2 into the bore 6 of the plug sleeve 1 and in thedirection of the bottom 9 the ring-shaped teeth 8 will tend to dig intothe material of the workpiece 4, thereby ensuring that the plug sleeve 1will be fixedly retained within the bore 10 of the workpiece 4. Owing tothe fact that not all of the teeth 8 simultaneously penetrate into thematerial of the walls surrounding the bore 10 of the workpiece 4, ratherthere is a progressive penetration of such teeth owing to the movementof the ball 2 progressively in the axial direction as it is being driveninto the bore 6 of the plug sleeve 1, the force required for driving theball 2 into the sleeve 1 is relatively low.The material of the plugwhich consists of metal is chosen such that it possesses a relativelyslight tendency to spring back into its original state after it has beenexpanded by the ball 2, thereby preventing any springing back of theregion of the sleeve which is behind the ball.

FIG. 3 illustrates a modified form of inventive plug which can beparticularly well manufactured in accordance with a deep-drawingtechnique. It will be seen that the plug sleeve 1 is provided at theregion of its floor or base 9 with a funnel-like construction 20 which,on the one hand, functions as a stop means for the ball 2 which has beendriven into the bore 6 of such plug sleeve 1 and, on the other hand,provides the function that this funnel-shaped floor 9 tends to spreadunder the action of the ball which is driven against the tip of thefunnel-shaped portion 20, and therefore provides an additional anchoringand sealing of the plug within the bore 10 of the workpiece 4.

With the embodiment of plug construction as depicted in FIG. 4 the plugsleeve 1 is provided at the side of the opening 17 with an outwardlydepending or extending collar or flange 11. Hence, when the sleeve 1 ofthis plug construction is inserted into the bore 10 of the workpiece 4the depending collar or flange 11 bears against the end portion 12 ofthe workpiece 4. The collar 11 must be dimensioned so strongly that itis capable of taking up the forces which are applied when the ball 2 isdriven into the bore of the plug sleeve 1. With this arrangement andowing to the provision of the depending collar 11 it is not necessary,as was the case with the embodiments of FIGS. 1 to 3, to bore out theworkpiece bore 10 such that it has a stepped configuration.

Now with the embodiment of plug construction as depicted in FIG. 5 thefloor or bottom 9 of the plug sleeve 1 is provided with an opening 13.During such time as the ball or sphere 2 is driven into the bore 6 ofthe sleeve 1 the marginal edge 14 of such sleeve is simultaneouslyturned or flanged inwardly. Useful as a tool for achieving this effectis a mandrel 15, shown to the right of FIG. 5, and which is equippedwith a ring shaped groove 18. In order to provide a reliable seal, thespace or compartment 16 thus formed within the confines of the inwardlyflanged sleeve 1 can be equipped with a suitable sealing means, whichmay be liquid or pasty or such space 16 can be provided with arubber-elastic sealing ring, all as merely schematically indicatedbyreference character 21.

FIG. 6 schematically illustrates the manner in which the teeth 8successively carry out a certain rolling or squeezing movement duringthe movement of the expanding means, namely the ball or sphere 2 in thedirection of the arrow A through the inner bore 6 of the plug sleeve 1.This rolling or squeezing motion of the teeth 8, even though it isrelatively small, facilitates the penetration of the teeth 8 into thematerial surrounding the bore 10 of the workpiece 4. During the axialmovement of the ball 2 and the therewith associated expansion of thematerial of the plug sleeve 1 the sawtoothshaped teeth 8 are rockedthrough an angle 0: so that during the expanding operation movement ofthese teeth occur.

It might here be mentioned that the ridge or spine 7 of each of theteeth 8 are located along a respective cone which enlarges in diameterin the direction of the opening 17 of the plug sleeve 1.

Instead of using a ball or sphere as the expanding element for the plugit would be possible to use a different configured or designed expansionelement which is provided with a ball-like or crown-like portion at theregion of the bore 6 of the plug.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto but may be otherwise variously embodied and practicedwithin the scope of the following claims.

What is claimed is:

l. A plug for closing the bores of workpieces, comprising a plug sleevehaving a plug bore and destined to be inserted into a bore of theworkpiece which is to be closed, the outside surface of said plug sleevebeing equipped with means for engaging with the material of theconfining wall of the bore of the workpiece to anchor the plug sleeve inthe workpiece bore, an expanding member which can be driven into thebore of the plug sleeve for radially expanding said plug sleeve, saidexpanding member being a ball possessing a substantially ball-likeconfiguration at least at the region intended to bear against said boreof the plug sleeve, and wherein said bore of said plug sleeve possessesat least an approximately cylindrical configuration, and

5. wherein said plug sleeve has an opening for receiving said ball in apre-mounted position within the plug bore, said ball in said pre-mountedposition being fixedly retained at said opening of the plug sleeve by aninwardly flanged sleeve portion.

2. The plug as defined in claim 1, wherein said ball is displaceablymounted in said plug bore for travel through a path of displacement inaxial direction between its pre-mounted position and until impactagainst the floor of the plug sleeve which corresponds to at leastapproximately one-half of the diameter of said ball.

3. A plug for closing bores of workpieces, comprising a substantiallycylindrical plug sleeve of substantially rigid deformable materialhaving a base end and an open end, said open end communicating with anaxially extending bore in said sleeve, the outside surface of saidsleeve having an annular anchoring portion including a plurality ofaxially spaced annularridges, the bore of said sleeve possessing asubstantially cylindrical portion extending between said open end ofsaid sleeve and said base end, an expanding member adapted to be driveninto said cylindrical portion of said bore of the sleeve and possessinga substantially ball-like configuration at least at the region thereofdirected toward said base end and having its largest diameter largerthan the diameter of said cylindrical portion of said bore, topermanently expand and anchor axially successive ones of said annularridges in the confining wall of the bore of the workpiece when drivingsaid expanding member from said open end towards said base end of saidsleeve within said cylindrical portion of said bore to progressivelyradially expand said sleeve, said open end having a seat enlarged withrespect to the diameter of the cylindrical portion of the sleeve toreceive said expanding member.

4. The plug as defined in claim 3, wherein said annulat ridges each havea sawtooth-shaped profile, each of said sawtooth-shaped ridges having anedge situated upon a cone which increases in diameter in the directionof said open end of said plug sleeve.

5. The plug as defined in claim 3, wherein said ridges are only disposedat the central region of the length of said plug sleeve.

6. The plug as defined in claim 3, wherein said base end of said plugsleeve has a floor portion possessing a substantially funnel-shapedconfiguration and which extends inwardly towards the lengthwise axis ofthe bore of the plug sleeve and serves as stop means for said expandingmember.

7. The plug as defined in claim 3, wherein said expanding member is aball.

8. The plug as defined in claim 7, wherein said ball is fixedly retainedin said seat by an inwardly flanged v sleeve portion in a pre-mountedposition.

9. The plug as defined in claim 8, wherein said ball is displaceablymounted in said plug bore for travel through a path of displacement inaxial direction between its pre-mounted position and until impactagainst the floor of the plug sleeve which corresponds to at leastapproximately one-half of the diameter of said ball. 1

10. The plug as defined in claim 3, wherein said open end of said sleeveis provided with a collar which extends radially outwardly of saidsleeve.

11. The plug as defined in claim 3, wherein said open end of said sleevepossesses an inwardly turned edge.

of the plugsleeve being provided with sealing means.

1. A plug for closing the bores of workpieces, comprising a plug sleevehaving a plug bore and destined to be inserted into a bore of theworkpiece which is to be closed, the outside surface of said plug sleevebeing equipped with means for engaging with the material of theconfining wall of the bore of the workpiece to anchor the plug sleeve inthe workpiece bore, an expanding member which can be driven into thebore of the plug sleeve for radially expanding said plug sleeve, saidexpanding member being a ball possessing a substantially ball-likeconfiguration at least at the region intended to bear against said boreof the plug sleeve, and wherein said bore of said plug sleeve possessesat least an approximately cylindrical configuration, and wherein saidplug sleeve has an opening for receiving said ball in a pre-mountedposition within the plug bore, said ball in said pre-mounted positionbeing fixedly retained at said opening of the plug sleeve by an inwardlyflanged sleeve portion.
 2. The plug as defined in claim 1, wherein saidball is displaceably mounted in said plug bore for travel through a pathof displacement in axial direction between its pre-mounted position anduntil impact against the floor of the plug sleeve which corresponds toat least approximately one-half of the diameter of said ball.
 3. A plugfor closing bores of workpieces, comprising a substantially cylindricalplug sleeve of substantially rigid deformable material having a base endand an open end, said open end communicating with an axially extendingbore in said sleeve, the outside surface of said sleeve having anannular anchoring portion including a plurality of axially spacedannular ridges, the bore of said sleeve possessing a substantiallycylindrical portion extending between said open end of said sleeve andsaid base end, an expanding member adapted to be driven into saidcylindrical portion of said bore of the sleeve and possessing asubstantially ball-like configuration at least at the region thereofdirected toward said base end and having its largest diameter largerthan the diameter of said cylindrical portion of said bore, topermanently expand and anchor axially successIve ones of said annularridges in the confining wall of the bore of the workpiece when drivingsaid expanding member from said open end towards said base end of saidsleeve within said cylindrical portion of said bore to progressivelyradially expand said sleeve, said open end having a seat enlarged withrespect to the diameter of the cylindrical portion of the sleeve toreceive said expanding member.
 4. The plug as defined in claim 3,wherein said annular ridges each have a sawtooth-shaped profile, each ofsaid sawtooth-shaped ridges having an edge situated upon a cone whichincreases in diameter in the direction of said open end of said plugsleeve.
 5. The plug as defined in claim 3, wherein said ridges are onlydisposed at the central region of the length of said plug sleeve.
 6. Theplug as defined in claim 3, wherein said base end of said plug sleevehas a floor portion possessing a substantially funnel-shapedconfiguration and which extends inwardly towards the lengthwise axis ofthe bore of the plug sleeve and serves as stop means for said expandingmember.
 7. The plug as defined in claim 3, wherein said expanding memberis a ball.
 8. The plug as defined in claim 7, wherein said ball isfixedly retained in said seat by an inwardly flanged sleeve portion in apre-mounted position.
 9. The plug as defined in claim 8, wherein saidball is displaceably mounted in said plug bore for travel through a pathof displacement in axial direction between its pre-mounted position anduntil impact against the floor of the plug sleeve which corresponds toat least approximately one-half of the diameter of said ball.
 10. Theplug as defined in claim 3, wherein said open end of said sleeve isprovided with a collar which extends radially outwardly of said sleeve.11. The plug as defined in claim 3, wherein said open end of said sleevepossesses an inwardly turned edge.
 12. The plug as defined in claim 11,wherein the floor of the sleeve is provided with an opening, saidexpanding member being a ball, and the intermediate space between theball and the inner wall bounding the bore of the plug sleeve beingprovided with sealing means.